The Philippine Rice Research Institute (PhilRice) has issued a crucial advisory for rice farmers to intensify pest monitoring efforts as the wet season heightens the risk of pest outbreaks.

This warning stems from the findings of the Pest Risk Identification and Management (PRIME) Project, a significant initiative under the Department of Agriculture aimed at protecting crops and preventing substantial yield losses.

Leonardo V. Marquez, a crop protection expert at PhilRice, underscored the importance of vigilant pest surveillance, especially during the rainy season when conditions are ideal for pest proliferation.

“Unmanaged infestations can lead to yield losses of 15% or more. Early detection and management are needed,” Marquez stated.

The PRIME Project, based on a comprehensive five-year survey across 53 provinces, has pinpointed the top five pests threatening rice crops: brown spot, deadheart, leaf blast, sheath blight, and whitehead. This analysis, which monitored 19 pests, revealed that pest incidents are more frequent and severe during the wet season.

Brown Spot Prevalence in Western Visayas

Brown spot, a fungal disease affecting rice at all growth stages, was particularly rampant in Western Visayas last December, with incidences exceeding 5% in Antique, Aklan, Capiz, Iloilo, and Negros Occidental. 

This disease can cause stunting, yellowing, leaf drying, short panicles, and empty grains. Marquez advised using high-quality seeds, applying potassium-rich fertilizers, and fungicides to mitigate its impact.

Deadheart Infestations in Iloilo

Deadheart, associated with stem borer infestations, showed high incidence rates in Iloilo. 

“Deadheart, where the central part of the panicle turns white and dies, can cause substantial yield loss if 30% of the crop is affected during flowering,” Marquez noted. 

He stressed the importance of monitoring stem borer moths, especially during the wet season, to determine when to take action.

Leaf Blast Concerns During Rainy Season

Leaf blast, another major concern, becomes more damaging during the rainy season. 

Effective management practices include avoiding excessive nitrate nitrogen, maintaining proper water depth, and burning affected rice straw to eliminate spores.

Sheath Blight Threat in Irrigated Fields

Sheath blight, characterized by grayish-brown lesions, poses a significant threat, particularly in irrigated fields with heavy rainfall and excessive nitrogen fertilization. 

The disease can reduce yields by up to 25% if left untreated and has been a concern in Antique, Capiz, Iloilo, and Negros Occidental.

Whitehead Problems from Stem Borer Attacks

Whiteheads, resulting from stem borer attacks, disrupt nutrient flow and lead to panicle death. Marquez recommended avoiding pesticide use for 30-40 days after planting, promoting beneficial insects, and monitoring butterfly populations. 

“Pesticides should only be used if caterpillar numbers exceed those of wasps. For future plantings, use resilient varieties, stagger planting, and manage fertilization properly,” he advised.

The PRIME Project, under the Rice Program of the Department of Agriculture-Bureau of Agricultural Research, focuses on pest management by assessing outbreak risk factors, developing mitigation strategies, and enhancing partners’ capabilities in remote sensing and pest risk mapping.

Rice farmers are encouraged to heed these recommendations to safeguard their crops and ensure a bountiful harvest despite the challenges posed by the wet season.